L8-10_ReproHO11 - EEMB 106 Lectures 8-9 Reproduction and...

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EEMB 106 – Lectures 8-9 – Reproduction and Development 1 I) Number of breeding opportunities Semelparous : spawn once/lifetime, then die Iteroparous : multiple spawns in a lifetime Daily, monthly, or seasonal II) Mating system Basis of mating systems is anisogamy – difference between egg and sperm sizes; leads to differences in how males and females maximize reproductive success: Females: maximize resource intake, convert this to eggs. Males: maximize matings; high potential mating success, leads to competition. Promiscuity : multiple partners for males and females – also known as polygamy ! Polygyny : multiple females for one male - in fishes, this is often serial, one female after another ! Polyandry : multiple males for one female - in fishes, this is most often simultaneous (group spawning) Monogamy : partners remain together for extended period of time III) Gender systems ! Gonochorism : one sexual tissue type per individual ! Hermaphroditism : an individual that has both ovarian and testicular tissue in a lifetime - Simultaneous : both gonadal tissues functional in one individual - Many deep-sea families, some gobies, some serranids - Advantages: - mate with whomever you meet - can nearly double reproductive output - but is evolutionarily unstable, vulnerable to male cheating - Sequential : a switch from one gonadal tissue to another. Protogynous (noun = protogyny): female first Protandrous (noun = protandry): male first Sex change can be explained by the size advantage model – relates sexual pattern to mating system. Simple definition: When expectations of offspring differ with size or age between
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This note was uploaded on 01/10/2012 for the course EEMB 106 taught by Professor Staff during the Spring '08 term at UCSB.

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L8-10_ReproHO11 - EEMB 106 Lectures 8-9 Reproduction and...

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